Sparda (Devil Arm)

The default weapon for Dante in DMC1 (in its Force Edge form). It is a momento of Dante's father, Sparda.

Role in Devil May Cry 3
It is revealed that the Force Edge is actually a "core" of Sparda's bulk power. In DMC3, Arkham intended to obtain Force Edge to rule to world, as a god. He aquired the Force Edge, and it granted him the power of Sparda. However, the power was too much for him and transformed him into a shapeless monster. After Dante works together with Vergil to defeat Arkham in the demon realm, the twin brothers fight for the ownership of Force Edge and the half amulets.

Vergil takes the Force Edge and uses it against Dante in their battle, however Dante is victorious. As the portal closes, Vergil decides to stay behind and vanishes into the darkness with one half of the amulet, leaving Dante the Force Edge along with his own half of the amulet.

Role in the original game
In Devil May Cry, the original game, Dante starts with the Force Edge. Dante gains access to the powerful sword Sparda by transforming Force Edge, after defeating Nelo Angelo and claiming Vergil's amulet. It is revealed that Sparda can only be unlocked by combining Force Edge and Sparda's amulet(s). Sparda bears the name of its original wielder, the Dark Knight Sparda, and actually transforms as needed for the situation. Its default form is a sword, but it can also change into a long pike or a scythe. On examination, the Force Edge can be seen within the design of the fully unlocked Sparda sword.